Geeks Gone Wild

Five years ago, Apple and Google didn't have much to do with each other's business. But now, as Apple's iPhone wars with rivals running Google's Android operating system, the two are direct competitors -- a situation that didn't escape the attention of regulators at the Federal Trade Commission, who announced an inquiry into Google and Apple's board overlap.

Google Pins San Francisco

Google CEO Eric Schmidt told the Associated Press that Levinson has been "a key part of Google's success these past five years" but didn't say why Levinson was leaving now.

Schmidt himself left Apple's board earlier this year, after maintaining there was no need for him to quit his position. Google's announcement of a planned operating system for personal computers, Chrome OS, posed a more direct threat to Apple's core business of making hardware and software for personal computers.

The companies have also feuded publicly over Google Voice, a Web-based telephony app that Apple has not allowed onto iPhones.

While Levinson and Schmidt's departures would seem to remove the appearance of a conflict, in reality, Apple and Google still retain strong boardroom ties. Two Apple board members, former vice president Al Gore and Intuit chairman Bill Campbell, also serve as senior advisors to Google.